Low-cost, highly homogeneous, large-diameter powder high-temperature alloy rods and their hot extrusion method

Abstract

This application relates to a low-cost, highly homogeneous, large-diameter powder high-temperature alloy bar and a hot extrusion method thereof, which belongs to the technical field of high-temperature alloy bar, and can solve the problems of conventional powder high-temperature alloy bar, such as small diameter, non-uniform structure, and low material utilization rate. The hot extrusion method includes the steps of injecting high-temperature alloy powder into a vacuum stainless steel shell jacket and hot isostatically pressing it to obtain a powder high-temperature alloy ingot; welding a front pad and a rear pad to the front end and rear end of the powder high-temperature alloy ingot, respectively, to obtain a first extrusion billet; preheating the first extrusion billet to 150-200°C, uniformly coating its surface with an antioxidant paint, heating it to 1040-1150°C and keeping it at that temperature to obtain a second extrusion billet; uniformly spraying a lubricant on the surface of the second extrusion billet, placing a glass mat on its front end, and extruding it into a preheated extrusion die to obtain an extrusion bar; and air-cooling the extrusion bar to room temperature and mechanically cutting off the non-stationary segments at the head and tail to obtain a powder high-temperature alloy bar.

Description

[Technical Field]

[0001] The present application relates to the technical field of high temperature alloy rods, and more particularly to low-cost, highly homogeneous, large-diameter powder high temperature alloy rods and a hot extrusion method thereof. [Background technology]

[0002] Powdered high-temperature alloys are high-temperature alloys manufactured using the powder metallurgy process. In powder metallurgy, powder particles are formed by rapid solidification of a small amount of liquid. Component segregation is limited to the size of the powder particles, eliminating the macrosegregation seen in traditional casting. At the same time, the powder obtained after rapid solidification has the advantages of uniform structure and fine grains, significantly improving the alloy's mechanical properties and thermal processing performance. Powdered high-temperature alloys are essential materials for key components such as turbine disks in modern high-performance aircraft engines. Due to their high degree of alloying, narrow hot-working window, and high deformation resistance, they require cladding extrusion.

[0003] The hot extrusion process is a processing process that applies high temperature and pressure to raw materials to change their properties. It combines the characteristics of hot compression and hot working deformation, which can significantly improve the metallurgical quality of the alloy and enhance and realize the alloy's potential performance. The alloy bars produced by the conventional hot extrusion method of powder high temperature alloy bars have small alloy bar diameters, uneven bar structures, large grain size variations, low bar material utilization rates, high production costs, and cannot be extruded into open billets with large extrusion ratios. Summary of the Invention

[0004] In view of the above analysis, the embodiments of the present application aim to provide a large-diameter powder high temperature alloy bar and a hot extrusion method therefor to solve at least one of the following problems associated with the conventional hot extrusion method of powder high temperature alloy bar: 1) the diameter of the alloy bar produced by the conventional hot extrusion method of powder high temperature alloy bar is small, making it impossible to produce a large-diameter bar; 2) the structure of the alloy bar produced by the conventional hot extrusion method of powder high temperature alloy bar is non-uniform and there is a large difference in grain size; 3) the utilization rate of the alloy bar produced by the conventional hot extrusion method of powder high temperature alloy bar is low, resulting in high production costs; and 4) the extrusion open billet cannot be extruded with a large extrusion ratio using the conventional hot extrusion method of powder high temperature alloy bar.

[0005] The objectives of this application are mainly achieved by the following technical solutions: Meanwhile, the present application provides a low-cost, highly homogeneous, large-diameter hot extrusion method for high-temperature alloy rods, the method comprising the following steps:

[0006] Step S1: The high-temperature alloy powder is injected into a vacuum stainless steel shell jacket and subjected to hot isostatic pressing to obtain a powder high-temperature alloy ingot.

[0007] Step S2: Weld a front pad and a rear pad to the front end and rear end of the powder high temperature alloy ingot, respectively, to obtain a first extrusion billet.

[0008] Step S3: After preheating the first extrusion billet to 150-200°C, an antioxidant paint is uniformly applied to the surface of the first extrusion billet, and the first extrusion billet is heated to 1040-1150°C and kept at that temperature to obtain a second extrusion billet.

[0009] Step S4: Spray lubricant evenly on the surface of the second extrusion billet, place a glass mat on the front end of the second extrusion billet, and put it into a preheated extrusion die and extrude it to obtain an extruded bar.

[0010] Step S5: The extruded rod is air-cooled to room temperature, and the non-stationary segments at the head and tail are mechanically cut off to obtain a powder high-temperature alloy rod.

[0011] Furthermore, in step S2, the axial cross section of the front pad is an axisymmetrical quasi-trapezoid shape with two arc-shaped sides.

[0012] Furthermore, the arc degree of the arc is 30° to 35°.

[0013] Furthermore, in step S3, the warming time is 7 to 24 hours.

[0014] Furthermore, in step S4, the extrusion die is preheated to a temperature of 150 to 200°C.

[0015] Furthermore, in step S4, the extrusion die angle is 90° to 130°.

[0016] Furthermore, in step S4, the extrusion speed is 20 to 25 mm / s.

[0017] Furthermore, in step S4, the extrusion ratio is (8-9):1.

[0018] On the other hand, the present application further provides a low-cost, highly homogeneous, large-diameter powder high-temperature alloy bar manufactured by the above-mentioned hot extrusion method.

[0019] Furthermore, the diameter of the low-cost, highly homogeneous, large-diameter powder high-temperature alloy bar is ≧300 mm.

[0020] Compared with the prior art, the present application can achieve at least one of the following beneficial effects: [Effects of the Invention]

[0021] 1. The hot extrusion method for high-temperature alloy rods in this application can reduce the preheating and spraying temperatures of the antioxidant paint, and spray after preheating at a low temperature, controlling the paint to dry slowly, and then raising the temperature to a high temperature, thereby ensuring that the antioxidant paint is not easily peeled off. The synergistic effect of the extrusion die angle and extrusion speed can ensure a large extrusion ratio and uniform structure of the extruded rods, and phenomena such as engine stalls can be avoided.

[0022] 2. The hot extrusion method of high-temperature alloy bars of this application, by using a specific extrusion front pad structure setting and synergistic effects with other process parameters in the hot extrusion process, can significantly reduce the degree of wrapping of the extruded front section bar compared with traditional hot extrusion methods, thereby eliminating the "mushroom-shaped head", thereby improving material utilization and reducing production costs, and the material utilization rate is >80%.

[0023] 3. The powder high temperature alloy bar obtained by the hot extrusion method of the present application has a diameter of ≥ 300mm, and at the same time, has a high material utilization rate, a uniform structure of the bar, the grain size of the core is 9-11 grade, the grain size of the edge is 9-10 grade, and the grain size difference is ≤ 1 grade.

[0024] In the present application, the above technical solutions can be combined with each other to realize more preferred combinations. Other features and advantages of the present application will be set forth in the following description, and in part will be apparent from the description or may be learned by practice of the present application. The objectives and other advantages of the present application may be realized and obtained by the contents particularly pointed out in the description and the accompanying drawings.

[0025] [Brief explanation of the drawings]

[0026] The accompanying drawings are for purposes of illustrating illustrative embodiments only and are not to be construed as limiting the present application, and like reference numerals refer to like elements throughout the accompanying drawings.

[0027] [Figure 1] 1 is a schematic diagram showing the structure of an extrusion billet provided in an example of the present application. [Figure 2] 1 is a photograph showing the structure of the core and edge of a low-cost, highly homogeneous, large-diameter powder high-temperature alloy bar produced in Example 1 of the present application. [Figure 3] FIG. 1 shows the head of a low-cost, highly homogeneous, large-diameter powder high-temperature alloy bar produced in Example 1 of the present application. [Figure 4] FIG. 1 shows the tail section of a low-cost, highly homogeneous, large-diameter powder high-temperature alloy bar produced in Example 1 of the present application. [Figure 5] FIG. 2 is a diagram showing the head of a powder high temperature alloy bar manufactured in Comparative Example 1. [Figure 6] FIG. 1 is a view showing the tail of a powder high temperature alloy bar manufactured in Comparative Example 1. [Figure 7] 1 is an actual diagram of a low-cost, highly homogeneous, large-diameter powder high-temperature alloy bar produced in Example 1 of the present application. [Figure 8] FIG. 2 is an actual view of a powder high-temperature alloy bar manufactured in Comparative Example 1. Specific Embodiments

[0028] Preferred embodiments of the present application will now be described in detail with reference to the accompanying drawings, which constitute a part of the present application and are not intended to limit the scope of the present application but to explain the principles of the present application together with the embodiments of the present application.

[0029] The present application provides a low-cost, highly homogeneous, large-diameter powder high-temperature alloy bar hot extrusion method, said method comprising the steps of:

[0030] Step S1: The high-temperature alloy powder is injected into a vacuum stainless steel shell jacket and subjected to hot isostatic pressing to obtain a powder high-temperature alloy ingot.

[0031] Step S2: Weld a front pad and a rear pad to the front end and rear end of the powder high temperature alloy ingot, respectively, to obtain a first extrusion billet.

[0032] Step S3: After preheating the first extrusion billet to 150 to 200°C, an anti-oxidation coating is uniformly applied to the surface of the extrusion billet, and the billet is heated to 1040 to 1150°C and kept at that temperature to obtain a second extrusion billet. Step S4: Spray lubricant evenly on the surface of the second extrusion billet, place a glass mat on the front end of the second extrusion billet, and put it into a preheated extrusion die and extrude it to obtain an extruded bar.

[0033] Step S5: The extruded rod is air-cooled to room temperature, and the non-stationary segments at the head and tail are mechanically cut off to obtain a powder high-temperature alloy rod.

[0034] Specifically, in step S1, the high temperature alloy powder is one of FGH4095, FGH4096, FGH4720Li, FGH4097, FGH4098 and fourth generation powder high temperature alloys, and the hot isostatic pressing conditions can be conventional hot isostatic pressing conditions according to the type of powder high temperature alloy to obtain a powder high temperature alloy ingot.

[0035] Specifically, in step S2, the cross section of the front pad is an axisymmetric, quasi-trapezoidal shape with two arc-shaped sides, and the arc angle is 30° to 35°. Exemplary arc angles are 31°, 32°, 33°, and 34°. When the front section of the extrusion billet is deformed, the metal at the edges and the metal at the center deform differently, resulting in the front pad wrapping around the bar and reducing the utilization rate of the bar. The axial cross section of the front pad of the present application is arc-shaped. Compared to conventional front pads (which have a circular axial cross section), the front pad with the arc angle significantly reduces the degree to which the front section of the extruded bar is wrapped around, eliminating the "mushroom-shaped head." The adoption of a front pad with this structure improves the utilization rate of the front section bar.

[0036] Specifically, in step S2, the radial shape and area of ​​the front pads and rear pads are made to match those of the ingot, and the thickness of the front pads and rear pads is set to 100 to 400 mm.

[0037] Specifically, in step S3, the first extrusion billet is preheated to 150 to 200°C, and then an antioxidant paint is uniformly applied to the surface of the first extrusion billet, and the paint is controlled to dry slowly.The billet is then placed in a heating furnace, heated to 1040 to 1150°C, and kept warm for 7 to 24 hours, making the antioxidant paint less likely to peel off. Illustratively, the preheating temperatures are 160°C, 170°C, 180°C, and 190°C, the heating temperatures are 1050°C, 1060°C, 1070°C, 1080°C, 1090°C, 1100°C, 1110°C, 1120°C, 1130°C, and 1140°C, and the heat-retention times are 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, and 24 hours. The antioxidant paint is any one of P35-a3, TE61-20, and ZS1051.

[0038] Specifically, in step S4, the extrusion die is preheated before extrusion. The preheating temperature is 150-200°C. For example, the die preheating temperature is 160°C, 170°C, 180°C, or 190°C. The die material itself has corresponding strength within a certain temperature range. The higher the preheating temperature, the smaller the extrusion resistance of the die itself, making the billet extrusion process smoother. However, if the temperature is too high, the die will completely lose its strength and be easily damaged. Considering all factors, the die preheating temperature should be 150-200°C.

[0039] After the second extrusion billet is removed from the furnace, a lubricant is sprayed evenly and directly onto the surface of the second extrusion billet without cooling. A glass mat is placed at the front end of the second extrusion billet and the billet is extruded into a preheated extrusion die at a die angle of 90° to 130°, an extrusion speed of 20 to 25 mm / s, and an extrusion ratio of (6 to 9):1 to obtain an extruded rod. Preferably, the extrusion ratio is (8 to 9):1. Illustratively, the extrusion die angles are 95°, 100°, 105°, 110°, 115°, 120°, and 125°, the extrusion speeds are 20.5 mm / s, 21 mm / s, 21.5 mm / s, 22 mm / s, 22.5 mm / s, 23 mm / s, 23.5 mm / s, 24 mm / s, and 24.5 mm / s, and the extrusion ratios are 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, and 9:1.

[0040] Furthermore, if the extrusion die angle is too small, the extrusion force will increase, and the extrusion force of the press will increase sharply. Due to the principle of action and reaction, the pressure acting on the jacket and ingot will increase, and the metal flow rate of the bar ingot and jacket material will increase, generating a large amount of heat in a short period of time. After the bar ingot undergoes dynamic recovery and dynamic recrystallization, the grain size of the bar surface will be significantly larger than that of the core structure, resulting in poor structure uniformity. If the extrusion die angle is too large, the extrusion force will act on the jacket, causing a long funnel-shaped defect at the tail of the bar and jacket, resulting in low material utilization. If the extrusion speed is too small, the original grain boundaries of the powder alloy will not be crushed sufficiently, resulting in insufficient recrystallization, and the grain size of the bar will not meet the standard. Due to the slow extrusion speed, the alloy will have a long recrystallization time, giving the grains enough time to grow, resulting in coarse and uneven grains. The large grain size will not meet the subsequent production standards. If the extrusion speed is too high, the bar ingot will gain too much energy per unit time, resulting in more recrystallization nuclei and the appearance of many fine grains. However, the large amount of heat generated by deformation will result in slow heat dissipation, leading to the appearance of large grains in the structure and the bar structure not meeting the standard. In this application, the synergistic effect of the extrusion die angle and extrusion speed can be used to ensure a large extrusion ratio and uniform structure of the extruded bar, thereby avoiding problems such as engine stalls. In actual operation, the extrusion in this application can be carried out using a 680MN extrusion-die forging dual-function unit.

[0041] Specifically, in step S5, the extruded bar is air-cooled to room temperature, and the transient segments of the head and tail are mechanically cut off to obtain a powder high-temperature alloy bar. The method of the present application can eliminate the "mushroom-shaped head" and significantly reduce the funnel-shaped defect in the tail of the bar, so that only a small amount of the head and tail can be removed to obtain the corresponding bar.

[0042] The present application further provides a low-cost, highly homogeneous, large-diameter powder high-temperature alloy bar manufactured by the above-mentioned hot extrusion method, wherein the diameter of the large-diameter powder high-temperature alloy bar is ≧300mm, and the low-cost, highly homogeneous, large-diameter powder high-temperature alloy bar has a core grain size of 8-11 grades, an edge grain size of 8-10 grades, and a grain size difference of ≦1 grade. Example 1

[0043] This embodiment provides a low-cost, highly homogeneous, large-diameter powder high-temperature alloy hot extrusion method, which includes the following steps: Step S1: The FGH4096 high-temperature alloy powder is injected into a vacuum stainless steel shell jacket (the cross section of the jacket is rectangular), and then hot isostatically pressed under argon gas protection to obtain a powder high-temperature alloy ingot, where the hot isostatic pressing temperature is 1160°C, the pressure is 130 MPa, and the size of the ingot is φ870mm.

[0044] Step S2: Weld a front pad and a rear pad to the front and rear ends of the powder high-temperature alloy ingot, respectively, to obtain a first extrusion billet. The structural schematic diagram of the extrusion billet is as shown in Figure 1, and the arc degree corresponding to the arc shape of the two sides is 32°.

[0045] Step S3: After preheating the first extrusion billet to 180°C, an anti-oxidation paint is uniformly applied to the surface of the first extrusion billet, and the first extrusion billet is placed in a heating furnace and heated to 1080°C and kept at that temperature for 10 hours to obtain a second extrusion billet.

[0046] Step S4: Spray glass powder evenly on the surface of the second extrusion billet, place a glass mat on the front end of the second extrusion billet, and put it into an extrusion die preheated to 180°C and extrude it to obtain an extruded rod, where the extrusion die angle is 100°, the extrusion speed is 22 mm / s, and the extrusion ratio is 8.4:1.

[0047] Step S5: The extruded bar is air-cooled to room temperature, and the non-steady segments of the head and tail are mechanically cut off to obtain a powder high-temperature alloy bar, in which a length of 280 mm is cut off from the head and a length of 330 mm is cut off from the tail to obtain a high-temperature alloy bar with a diameter of 300 mm and a steady segment length of 4400 mm. Example 2

[0048] The hot extrusion method for low-cost, highly homogeneous, large-diameter powder high-temperature alloys in this example is similar to that in Example 1, except that in step S4, the extrusion die angle is 90°, the extrusion speed is 25 mm / s, and the extrusion ratio is 6:1. Example 3

[0049] The hot extrusion method for low-cost, highly homogeneous, large-diameter powder high-temperature alloy in this example is similar to that in Example 1, except that in step S4, the extrusion die angle is 130°, the extrusion speed is 20 mm / s, and the extrusion ratio is 9:1. Example 4

[0050] The hot extrusion method for producing a low-cost, highly homogeneous, large-diameter powder high-temperature alloy in this embodiment is the same as that in Example 1, except that the preheating temperature in step S3 is 150°C. Example 5

[0051] The hot extrusion method for producing a low-cost, highly homogeneous, large-diameter powder high-temperature alloy in this embodiment is the same as that in Example 1, except that the preheating temperature in step S3 is 200°C. Example 6

[0052] The hot extrusion method for producing low-cost, highly homogeneous, large-diameter powder high-temperature alloys in this example is the same as in Example 1, except that in step S3, the extrusion billet is heated to 1120°C and kept at that temperature for 16 hours. Example 7

[0053] The hot extrusion method for producing low-cost, highly homogeneous, large-diameter powder high-temperature alloys in this example is the same as in Example 1, except that in step S3, the extrusion billet is heated to 1040°C and kept at that temperature for 7 hours. Example 8

[0054] The hot extrusion method for producing low-cost, highly homogeneous, large-diameter powder high-temperature alloys in this example is the same as in Example 1, except that in step S3, the extrusion billet is heated to 1150°C and kept at that temperature for 24 hours. Example 9

[0055] The hot extrusion method for low-cost, highly homogeneous, large-diameter powder high-temperature alloy in this embodiment is similar to that in Example 1, except that in step S2, the arc degree corresponding to the arc shape of the two side edges of the front pad of the extruded billet is 30°. Example 10

[0056] The hot extrusion method for low-cost, highly homogeneous, large-diameter powder high-temperature alloy in this embodiment is similar to that in Example 1, except that in step S2, the arc degree corresponding to the arc shape of the two side edges of the front pad of the extruded billet is 35°. Comparative Example 1

[0057] This comparative example provides a large diameter powder high temperature alloy hot extrusion method, which includes the following steps:

[0058] Step S1: The FGH4096 high-temperature alloy powder is injected into a vacuum stainless steel shell jacket (cross section of the jacket) and hot isostatically pressed under argon gas protection to obtain a powder high-temperature alloy ingot, where the hot isostatic pressing temperature is 1160°C, the pressure is 130 MPa, and the size of the ingot is φ870 mm.

[0059] Step S2: Weld a front pad and a rear pad to the front end and rear end of the powder high temperature alloy ingot, respectively, to obtain a first extrusion billet, where the front pad is a square block. Step S3: After preheating the first extrusion billet to 800°C, an anti-oxidation paint is uniformly applied to the surface of the first extrusion billet, and the first extrusion billet is placed in a heating furnace and heated to 1080°C and kept at that temperature for 10 hours to obtain a second extrusion billet.

[0060] Step S4: Spray glass powder evenly on the surface of the second extrusion billet, place a glass mat at the front end of the second extrusion billet, and put it into an extrusion die preheated to 180°C and extrude it to obtain an extruded rod, where the extrusion die angle is 60°, the extrusion speed is 30 mm / s, and the extrusion ratio is 8.5:1.

[0061] Step S5: The extruded bar is air-cooled to room temperature, and the non-steady segments of the head and tail are mechanically cut off to obtain a powder high-temperature alloy bar, in which a length of 600 mm is cut off from the head and a length of 700 mm is cut off from the tail to obtain a high-temperature alloy bar with a diameter of 300 mm and a steady segment length of 3800 mm. Comparative Example 2

[0062] The hot extrusion method of the powder high temperature alloy in this comparative example is the same as that in Example 1, except that in step S4, the extrusion die angle is 85°, the extrusion speed is 22 mm / s, and the extrusion ratio is 8.4:1. Comparative Example 3

[0063] The hot extrusion method of the powder high temperature alloy in this comparative example is the same as that in Example 1, except that in step S4, the extrusion die angle is 135°, the extrusion speed is 22 mm / s, and the extrusion ratio is 8.4:1. Comparative Example 4

[0064] The hot extrusion method of the powder high temperature alloy in this comparative example is the same as that in Example 1, except that in step S4, the extrusion die angle is 100°, the extrusion speed is 18 mm / s, and the extrusion ratio is 8.4:1. Comparative Example 5

[0065] The hot extrusion method of the powder high temperature alloy in this comparative example is the same as that in Example 1, except that in step S4, the extrusion die angle is 100°, the extrusion speed is 26 mm / s, and the extrusion ratio is 8.4:1. Comparative Example 6

[0066] The hot extrusion method of the powder high temperature alloy in this comparative example is the same as that in Example 1, except that in step S4, the extrusion die angle is 85°, the extrusion speed is 26 mm / s, and the extrusion ratio is 8.4:1. Comparative Example 7

[0067] The hot extrusion method of the powder high temperature alloy in this comparative example is the same as that in Example 1, except that in step S4, the extrusion die angle is 135°, the extrusion speed is 18 mm / s, and the extrusion ratio is 8.4:1. Comparative Example 8

[0068] The hot extrusion method for the large-diameter powder high-temperature alloy in this comparative example was the same as in Example 1, except that in step S3, the extrusion billet was heated to 1170°C and kept at that temperature for 30 hours. Comparative Example 9

[0069] The hot extrusion method of the large-diameter powder high-temperature alloy in this comparative example is the same as that in Example 1, except that in step S2, the arc degree corresponding to the arc shape of the two side edges of the front pad of the extrusion billet is 25°. Comparative Example 10

[0070] The hot extrusion method of the large-diameter powder high-temperature alloy in this comparative example is the same as that in Example 1, except that in step S2, the arc degree corresponding to the arc shape of the two side edges of the front pad of the extruded billet is 40°.

[0071] Figure 2 is a photograph showing the structure of the core and edge of a large-diameter powder high-temperature alloy bar produced in Example 1 of the present application. Here, numbers 1 to 15 correspond to samples taken at equal intervals on a radius extending in the direction of 1 to 15 in the cross section of the rear end surface of the bar, with 1 representing the center position of the cross section and 15 representing one edge point. As can be seen from the figure, the structure of the bar obtained in Example 1 has a grain size grade difference from the core to the edge of ≦1. The grain size and grade difference from the core to the edge at the same position of the alloy bars obtained in different Examples and Comparative Examples are shown in Table 1.

[0072] 3-6 are schematic diagrams of the head and tail of a large-diameter powder high-temperature alloy bar produced in Example 1 of the present application, and the head and tail of a bar produced in Comparative Example 1, respectively. As can be seen from the figures, the bar obtained in the present application does not have the problem of a "mushroom-shaped head." At the same time, the funnel-shaped defect in the tail of the bar is significantly reduced, which can significantly improve material utilization and thereby reduce manufacturing costs. The sizes and material utilization of the bars obtained in different Examples and Comparative Examples of the present application are shown in Table 2.

[0073] FIG. 7 is a photograph of a large-diameter powder high temperature alloy bar produced in Example 1 of the present application. FIG. 8 is a photograph of a bar produced in Comparative Example 1. From the photograph, it can be further confirmed that the bar obtained by the hot extrusion method of the present application does not have a "mushroom-shaped head" and that the funnel-shaped defect in the tail is significantly reduced. On the other hand, the head of the bar obtained by the hot extrusion method of Comparative Example 1 was found to have a periodic crack problem. At the same time, the data in Table 2 also show that the length of the tail trimmed during the production process of the powder high temperature alloy bar in the example is much lower than the length of the tail trimmed during the production process of the powder high temperature alloy bar of the same length and specifications in the comparative example. This indicates that the funnel-shaped defect in the tail of the bar obtained by the hot extrusion method of the present application is significantly reduced.

[0074] As can be seen from Tables 1 and 2, the powder high temperature alloy bar produced by the method of the present application has a diameter of ≥ 300 mm, and at the same time, the bar has a uniform structure, the grain size of the core is 9-11 grade, the grain size of the edge is 9-10 grade, and the grain size difference is ≤ 1 grade.

[0075] [Table 1]

[0076] [Table 2]

[0077] The above are merely preferred specific embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any modifications or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. [Explanation of symbols]

[0078] 1 ingot 2 front pads 3 rear pad

Claims

1. Step S1: injecting the high-temperature alloy powder into a vacuum stainless steel shell jacket and hot isostatic pressing the powder to obtain a high-temperature alloy ingot; Step S2: welding a front pad and a rear pad to the front end and the rear end of the powder high temperature alloy ingot, respectively, to obtain a first extrusion billet; Step S3 of preheating the first extrusion billet to 150 to 200°C, uniformly applying an anti-oxidation coating to the surface of the first extrusion billet, heating it to 1040 to 1150°C, and maintaining the temperature to obtain a second extrusion billet; Step S4: spraying lubricant evenly on the surface of the second extrusion billet, placing a glass mat on the front end of the second extrusion billet, and then extruding the billet into a preheated extrusion die to obtain an extruded bar; and step S5 of air-cooling the extruded rod to room temperature and mechanically cutting off the non-steady head and tail segments to obtain a powder high-temperature alloy rod. A method for hot extrusion of powder high temperature alloy rods at low cost and with high homogeneity, characterized by:

2. 2. The hot extrusion method according to claim 1, wherein in step S2, the axial cross section of the front pad is an axisymmetrical quasi-trapezoid with two arc-shaped sides.

3. 3. The hot extrusion method according to claim 2, wherein the arc angle is 30° to 35°.

4. 2. The hot extrusion method according to claim 1, wherein in step S3, the warming time is 7 to 24 hours.

5. 2. The hot extrusion method according to claim 1, wherein in step S4, the extrusion die is preheated to a temperature of 150 to 200°C.

6. 6. The hot extrusion method according to claim 5, wherein in step S4, the extrusion die angle is 90° to 130°.

7. 7. The hot extrusion method according to claim 6, wherein in step S4, the extrusion speed is 20-25 mm / s.

8. 8. The hot extrusion method according to claim 7, wherein in step S4, the extrusion ratio is 8-9:

1.

9. A low-cost, highly homogeneous, large-diameter powder high-temperature alloy bar produced by the hot extrusion method according to any one of claims 1 to 8.

10. 10. The low-cost, highly homogeneous, large-diameter powder high-temperature alloy bar according to claim 9, wherein the diameter of the large-diameter powder high-temperature alloy bar is ≧300 mm.

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